The present invention relates generally to a coated medical device and more particularly to a coated stent. Stents, grafts, stent-grafts, vena cava filters and similar implantable medical devices, collectively referred to hereinafter as stents, are radially expandable endoprostheses which are typically implants capable of being implanted transluminally and enlarged radially after being introduced percutaneously. Stents may be implanted in a variety of body lumens or vessels such as within the vascular system, esophagus, gastrointestinal tract, large and small intestine, biliary ducts, pancreas ducts, pulmonary and urinary tracts, etc. Stents may be used to reinforce body vessels and to prevent restenosis following angioplasty in the vascular system. Stents may also be used to open strictures. They may be self-expanding, mechanically expandable or hybrid expandable.
Stents are typically tubular members that are radially expandable from a reduced diameter configuration for delivery through a patient's body lumen to an expanded configuration once deployed at the treatment site.
Stents may be constructed from a variety of materials such as stainless steel, ELGILOY® (cobalt-chromium-nickel alloy), nickel, titanium, nitinol, shape memory polymers, other polymeric materials, etc. For metallic stents, a stent may be typically formed from a tubular member, either extruded or formed from a sheet, in which a pattern is subsequently formed by etching or cutting material from the tubular member.
Polymeric stents formed from a variety of thermoplastic polymer materials may be formed by weaving or braiding fibers or filaments.
Stents may further be provided with a cover, such as a silicone cover to prevent tissue ingrowth.
Desirable stent properties include sufficient flexibility to be able to conform to the tortuous body lumen during delivery, yet sufficiently rigid to resist migration once deployed at the treatment site.
In some stents, the compressible and flexible properties that assist in stent delivery may also result in a stent that has a tendency to migrate from its originally deployed position. Stent covering may contribute to migration as well. Stent migration affects many endoscopic stents including esophageal, pancreatic and biliary stents. Risk factors associated with stent migration are discussed in Incidence and risk factors for biliary and pancreatic stent migration, Johanson J F, Schmah. M J, Geenen J E. Gastrointest Endosc. 1992 May-June; 38(3):341-6.
It is thus desirable to provide a stent configuration that resists migration following deployment.
Commonly assigned US Patent Publication No. 20090098176, the entire content of which is incorporated by reference herein, discloses medical devices with triggerable bioadhesives.